Difference between pages "Prefetch" and "Mac OS X"

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Windows Prefetch files, introduced in [[Windows|Windows XP]], are designed to speed up the application startup process. Prefetch files contain the name of the executable, a Unicode list of DLLs used by that executable, a count of how many times the executable has been run, and a timestamp indicating the last time the program was run. Although Prefetch is present in Windows 2003, by default it is only enabled for boot prefetching. The feature is also found in [[Windows|Windows Vista]], where it has been augmented with [[SuperFetch]], [[ReadyBoot]], and [[ReadyBoost]]. For SSD drives Prefetch is disabled by default [http://blogs.msdn.com/b/e7/archive/2009/05/05/support-and-q-a-for-solid-state-drives-and.aspx].
 
  
Up to 128 Prefetch files are stored in the <tt>%SystemRoot%\Prefetch</tt> directory [http://blogs.msdn.com/ryanmy/archive/2005/05/25/421882.aspx]. Each file in that directory should contain the name of the application, a dash, and then an eight character hash of the location from which that application was run, and a <tt>.pf</tt> extension. The filenames should be all uppercase except for the extension. The format of hashes is not known. A sample filename for [[md5deep]] would look like: <tt>MD5DEEP.EXE-4F89AB0C.pf</tt>. If an application is run from two different locations on the drive (i.e. the user runs <tt>C:\md5deep.exe</tt> and then <tt>C:\Apps\Hashing\md5deep.exe</tt>), there will be two different prefetch files in the Prefetch folder.
+
Apple Inc.'s Macintosh OS X (pronounced "'''OS Ten'''") is the operating system distributed with Apple computers. It includes heavily used several programs by default, including [[Apple Mail]], a web browser called [[Apple Safari | Safari]], and an [[Apple Address Book]], and [[iCal]].  
  
== File format ==
+
== Disk image types ==
Each Prefetch file has a 4-byte signature (at offset 4) "SCCA" (or in hexadecimal notation 0x53 0x43 0x43 0x41). The signature is assumed to be preceded by a 4-byte format version indicator:
+
* 17 (0x00000011) for [[Windows XP]] and [[Windows 2003]]
+
* 23 (0x00000017) for [[Windows Vista]], [[Windows 2008]], [[Windows 7]] and [[Windows 2012]] (note Windows 2012 has not been confirmed)
+
* 26 (0x0000001a) for [[Windows 8|Windows 8.1]] (note this could be Windows 8 as well but has not been confirmed)
+
  
For more information about the file format see: [[Windows Prefetch File Format]]
+
Mac OS X has support for various disk image types build-in, some of which are:
 +
* read-write disk image (.dmg) some of which use the [[Raw Image Format]]
 +
* [[Sparse Image format|Sparse disk image (.spareimage)]]
 +
* [[Sparse Bundle Image format|Sparse bundle disk image (.sparsebundle)]]
  
== Metadata ==
+
== Burn Folder ==
The Prefetch file contains various metadata.
+
* The executable's name, up to 29 characters.
+
* The run count, or number of times the application has been run.
+
* Volume related information, like volume path and volume serial number.
+
* The size of the Prefetch file (sometimes referred to as end of file (EOF)).
+
* The files and directories that were used doing the application's start-up.
+
  
=== Timestamps ===
+
Mac OS X Burn Folder:
The Prefetch file contains 2 types of timestamps
+
<pre>
* The time when the application was last ran (executed). Version 26 of the Prefetch format maintains 7 previous last run times.
+
$NAME.fpbf
* The volume creation time (part of the volume information) of the volume the Prefetch file was created on.
+
</pre>
  
The file system creation time of the Prefetch file indicates the first time the application was executed. Both the file system modification time of the Prefetch file and the embedded last run time indicate the last time the application was executed.
+
This folder normally contains [[Mac OS X Alias Files|alias files]] (similar to LNK files under Windows). Which should have the following signature.
 +
<pre>
 +
00000000  62 6f 6f 6b 00 00 00 00  6d 61 72 6b 00 00 00 00  |book....mark....|
 +
</pre>
  
== Prefetch hash ==
+
These [[Mac OS X Alias Files|alias files]] contain additional date and time values.
There are multiple known hashing functions to be used for prefetch file filename hashing, namely:
+
* SCCA XP hash function; used on Windows XP and Windows 2003
+
* SCCA Vista hash function; used on Windows Vista
+
* SCCA 2008 hash function; used on Windows 2008, Windows 7, (possibly: Windows 2012) and Windows 8 (including 8.1)
+
  
=== SCCA XP hash function ===
+
Also check the following files for references to deleted .fpbf paths:
A Python implementation of the SCCA XP hash function:
+
<pre>
 +
/Users/$USERNAME/Library/Preferences/com.apple.finder.plist
 +
/Users/$USERNAME/Library/Preferences/com.apple.sidebarlists.plist
 +
</pre>
  
 +
Actual burning of optical media is logged in:
 
<pre>
 
<pre>
def ssca_xp_hash_function(filename):
+
/var/log/system.log
    hash_value = 0
+
/Users/$USERNAME/Library/Logs/DiscRecording.log
    for character in filename:
+
/private/var/.logs_exporter/cache/Users/$USERNAME/Library/Logs/DiscRecording.log
        hash_value = ((hash_value * 37) + ord(character)) % 0x100000000
+
</pre>
        hash_value = (hash_value * 314159269) % 0x100000000
+
 
        if hash_value > 0x80000000:
+
== HFS/HFS+ date and time values ==
            hash_value = 0x100000000 - hash_value
+
 
 +
In HFS+ date and time values are stored in an unsigned 32-bit integer containing the number of seconds since January 1, 1904 at 00:00:00 (midnight) UTC (GMT). This is slightly different from HFS where the date and time value are stored using the local time. The maximum representable date is February 6, 2040 at 06:28:15 UTC (GMT). The date values do not account for leap seconds. They do include a leap day in every year that is evenly divisible by four. This is sufficient given that the range of representable dates does not contain 1900 or 2100, neither of which have leap days. Also see: [http://web.archive.org/web/20090214212148/http://developer.apple.com/technotes/tn/tn1150.html Technical Note TN1150 - HFS Plus Volume Format]
 +
 
 +
Converting HFS/HFS+ date and time values with Python:
 +
<pre>
 +
import datetime
  
    return (abs(hash_value) % 1000000007) % 0x100000000
+
print datetime.datetime( 1904, 1, 1 ) + datetime.timedelta( seconds=0xCBDAF25B )
 
</pre>
 
</pre>
  
=== SCCA Vista hash function ===
+
== Launch Agents ==
A Python implementation of the SCCA Vista hash function:
+
<pre>
 +
/System/Library/LaunchAgents/
 +
</pre>
  
 +
== Launch Daemons ==
 
<pre>
 
<pre>
def ssca_vista_hash_function(filename):
+
/Library/LaunchDaemons/
    hash_value = 314159
+
/System/Library/LaunchDaemons/
    for character in filename:
+
        hash_value = ((hash_value * 37) + ord(character)) % 0x100000000
+
    return hash_value
+
 
</pre>
 
</pre>
  
=== SCCA 2008 hash function ===
+
== Startup Items ==
A Python implementation of the SCCA 2008 hash function:
+
<pre>
 +
/Library/StartupItems/
 +
/System/Library/StartupItems/
 +
</pre>
  
 +
== Quarantine event database ==
 +
See [http://menial.co.uk/blog/2011/06/16/mac-quarantine-event-database/]
 +
 +
Snow Leopard and earlier
 
<pre>
 
<pre>
def ssca_2008_hash_function(filename):
+
/Users/$USER/Library/Preferences/com.apple.LaunchServices.QuarantineEvents
    hash_value = 314159
+
</pre>
    filename_index = 0
+
    filename_length = len(filename)
+
    while filename_index + 8 < filename_length:
+
        character_value = ord(filename[filename_index + 1]) * 37
+
        character_value += ord(filename[filename_index + 2])
+
        character_value *= 37
+
        character_value += ord(filename[filename_index + 3])
+
        character_value *= 37
+
        character_value += ord(filename[filename_index + 4])
+
        character_value *= 37
+
        character_value += ord(filename[filename_index + 5])
+
        character_value *= 37
+
        character_value += ord(filename[filename_index + 6])
+
        character_value *= 37
+
        character_value += ord(filename[filename_index]) * 442596621
+
        character_value += ord(filename[filename_index + 7])
+
        hash_value = ((character_value - (hash_value * 803794207)) % 0x100000000)
+
        filename_index += 8
+
  
    while filename_index < filename_length:
+
<pre>
      hash_value = (((37 * hash_value) + ord(filename[filename_index])) % 0x100000000)
+
SELECT datetime(LSQuarantineTimeStamp + 978307200, "unixepoch") as LSQuarantineTimeStamp, LSQuarantineAgentName, LSQuarantineOriginURLString, LSQuarantineDataURLString from LSQuarantineEvent;
      filename_index += 1
+
</pre>
  
    return hash_value
+
Lion and later
 +
<pre>
 +
/Users/$USER/Library/Preferences/com.apple.LaunchServices.QuarantineEventsV2
 
</pre>
 
</pre>
  
== Registry Keys ==
+
== sleepimage ==
 +
This file is similar to the hibernation file on Windows.
 
<pre>
 
<pre>
Key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\PrefetchParameters
+
/private/var/vm/sleepimage
 
</pre>
 
</pre>
  
The EnablePrefetcher Registry value can be used to disable prefetch.
+
Also see: [http://osxdaily.com/2010/10/11/sleepimage-mac/]
  
== See Also ==
+
== Package Files (.PKG) ==
* [[Windows Prefetch File Format]]
+
Package Files (.PKG) are XAR archives [http://en.wikipedia.org/wiki/Xar_(archiver)] that contain a cpio archive and metadata [http://s.sudre.free.fr/Stuff/Ivanhoe/FLAT.html].
* [[SuperFetch]]
+
* [[Prefetch XML]]
+
* [[Windows]]
+
  
== External Links ==
+
== Also see ==
* [http://msdn.microsoft.com/msdnmag/issues/01/12/XPKernel/default.aspx More detail from Microsoft]
+
* [[MacOS Process Monitoring]]
* [http://en.wikipedia.org/wiki/Prefetcher Wikipedia Prefetcher]
+
* [[Acquiring a MacOS System with Target Disk Mode]]
* [http://msdn.microsoft.com/en-us/library/ms940847(v=winembedded.5).aspx MSDN: Disabling Prefetch]
+
* [[Converting Binary Plists]]
* [http://www.microsoft.com/whdc/driver/kernel/XP_kernel.mspx Kernel Enhancements for Windows XP], by [[Microsoft]], January 13, 2003 (Microsoft's description of Prefetch when Windows XP was introduced)
+
* [[FileVault Disk Encryption]]
* [http://blogs.msdn.com/b/ryanmy/archive/2005/05/25/421882.aspx Misinformation and the The Prefetch Flag], MSDN Blogs, May 25, 2005
+
* [[File Vault]]
* [http://windowsir.blogspot.ch/2005/07/prefetch-file-metadata.html Prefetch file metadata], by [[Harlan Carvey]], July 13, 2005
+
* [http://windowsir.blogspot.ch/2006/04/prefetch-files-revisited.html Prefetch files, revisited], by [[Harlan Carvey]], April 13, 2006
+
* [http://blogs.msdn.com/b/e7/archive/2009/05/05/support-and-q-a-for-solid-state-drives-and.aspx Support and Q&A for Solid-State Drives], by Steven Sinofsky, May 5, 2009
+
* [http://computer-forensics.sans.org/blog/2009/08/05/de-mystifying-defrag-identifying-when-defrag-has-been-used-for-anti-forensics-part-1-windows-xp/ De-mystifying Defrag: Identifying When Defrag Has Been Used for Anti-Forensics (Part 1 - Windows XP)], by [[Chad Tilbury]], August 5, 2009
+
* [http://www.swiftforensics.com/2010/04/the-windows-prefetchfile.html Windows Prefetch File (old blog entry from 42 LLC)], by [[Yogesh Khatri]], April 14, 2010
+
* [http://www.dfinews.com/articles/2010/12/decoding-prefetch-files-forensic-purposes-part-1 Decoding Prefetch Files for Forensic Purposes: Part 1], by [[Mark Wade]], December 8, 2010
+
* [http://crucialsecurityblog.harris.com/2011/04/11/prefetch-files-at-face-value/ Prefetch Files at Face Value], by [[Mark Wade]], April 11, 2011
+
* [http://kitrap08.blogspot.hk/2011/07/windows-logical-prefetcher.html Windows Logical Prefetcher], TTS blog, July 30, 2011 (article is in Russian)
+
* [http://labit.in/pliki-prefetch-w-windows/ Prefetch i niedokładny licznik] by Paweł Hałdrzyński, August 20, 2011 (article in Polish; uncertain about the year of publication)
+
* [http://windowsir.blogspot.ch/2012/03/prefetch-analysis-revisited.html Prefetch Analysis, Revisited], by [[Harlan Carvey]], March 8, 2012
+
* [http://windowsir.blogspot.ch/2012/03/prefetch-analysis-revisitedagain.html Prefetch Analysis, Revisited...Again...], by [[Harlan Carvey]], March 15, 2012
+
* [http://www.hexacorn.com/blog/2012/06/13/prefetch-hash-calculator-a-hash-lookup-table-xpvistaw7w2k3w2k8/ Prefetch Hash Calculator + a hash lookup table xp/vista/w7/w2k3/w2k8], Hexacorn blog, June 13, 2012
+
* [http://www.hexacorn.com/blog/2012/10/29/prefetch-file-names-and-unc-paths/ Prefetch file names and UNC paths], Hexacorn blog, October 29, 2012
+
* [http://journeyintoir.blogspot.ch/2012/12/ntosboot-prefetch-file.html NTOSBOOT Prefetch File], by [[Corey Harrell]], December 5, 2012
+
* [http://www.invoke-ir.com/2013/09/whats-new-in-prefetch-for-windows-8.html What's New in the Prefetch for Windows 8??], by Jared Atkinson, September 21, 2013
+
* [http://www.swiftforensics.com/2013/10/windows-prefetch-pf-files.html?m=1 Windows Prefetch (.PF) files], by [[Yogesh Khatri]], October 21, 2013
+
* [http://i.imgur.com/riuljsK.jpg Prefetch 101 -  a Windows 8 Prefetch file walkthrough], by Jared Atkinson, 2014
+
  
== Tools ==
+
=== Formats ===
 +
* [[Basic Security Module (BSM) file format]]
 +
* [[Property list (plist)]]
 +
 
 +
== External Links ==
 +
* [http://www.apple.com/macosx/ Official website]
 +
* [http://en.wikipedia.org/wiki/OS_X Wikipedia entry on OS X]
 +
* [http://menial.co.uk/blog/2011/06/16/mac-quarantine-event-database/ Quarantine event database]
 +
* [http://www2.tech.purdue.edu/cit/Courses/cit556/readings/MacForensicsCraiger.pdf Mac Forensics: Mac OS X and the HFS+ File System] by P. Craiger
 +
* [http://web.me.com/driley/iWeb/Previous_files/Directory_Services_Overview.pdf Mac OS X Directory Services Integration including Active Directory]
 +
* [http://digitalinvestigation.wordpress.com/2012/04/04/geek-post-nskeyedarchiver-files-what-are-they-and-how-can-i-use-them/ NSKeyedArchiver files – what are they, and how can I use them?]
 +
* [http://krypted.com/mac-os-x/command-line-alf-on-mac-os-x/ Command Line ALF on Mac OS X]
 +
* [http://newosxbook.com/DMG.html Demystifying the DMG File Format]
 +
* [https://code.google.com/p/mac-security-tips/wiki/ALL_THE_TIPS mac-security-tips]
  
=== Commercial ===
+
=== Apple Examiner ===
 +
* [http://www.appleexaminer.com/ The Apple Examiner]
 +
* [http://www.appleexaminer.com/MacsAndOS/Analysis/USBOSX/USBOSX.html USB Entries on OS X]
 +
* [http://www.appleexaminer.com/Downloads/MacForensics.pdf Macintosh Forensics - A Guide for the Forensically Sound Examination of a Macintosh Computer] by Ryan R. Kubasiak
  
=== Free - Non Open Source ===
+
=== iCloud ===
* [http://www.woanware.co.uk/forensics/prefetchforensics.html PrefetchForensics], PrefetchForensics is an application to extract information from Windows Prefetch files
+
* [http://support.apple.com/kb/HT4865?viewlocale=en_US&locale=en_US iCloud: iCloud security and privacy overview]
* [http://redwolfcomputerforensics.com/index.php?option=com_content&task=view&id=42&Itemid=55 Prefetch-Parser], Parse the prefetch files and display information
+
* [http://www.mitec.cz/wfa.html Windows File Analyzer] - Parses Prefetch files, thumbnail databases, shortcuts, index.dat files, and the recycle bin
+
* [http://www.tzworks.net/prototype_page.php?proto_id=1 Windows Prefetch Parser (pf)], Free tool that can be run on Windows, Linux or Mac OS-X
+
  
=== Open Source ===
+
[[Category:Mac OS X]]
* [https://code.google.com/p/prefetch-tool/ prefetch-tool], Script to extract information from windows prefetch folder
+
[[Category:Operating systems]]
* [http://bitbucket.cassidiancybersecurity.com/prefetch-parser prefetch-parser], Standalone Python tools that parses Windows prefetch files and extracts all known and forensically relevant artefacts contained.
+

Revision as of 08:19, 14 April 2014

Information icon.png

Please help to improve this article by expanding it.
Further information might be found on the discussion page.

Apple Inc.'s Macintosh OS X (pronounced "OS Ten") is the operating system distributed with Apple computers. It includes heavily used several programs by default, including Apple Mail, a web browser called Safari, and an Apple Address Book, and iCal.

Disk image types

Mac OS X has support for various disk image types build-in, some of which are:

Burn Folder

Mac OS X Burn Folder:

$NAME.fpbf

This folder normally contains alias files (similar to LNK files under Windows). Which should have the following signature.

00000000  62 6f 6f 6b 00 00 00 00  6d 61 72 6b 00 00 00 00  |book....mark....|

These alias files contain additional date and time values.

Also check the following files for references to deleted .fpbf paths:

/Users/$USERNAME/Library/Preferences/com.apple.finder.plist
/Users/$USERNAME/Library/Preferences/com.apple.sidebarlists.plist

Actual burning of optical media is logged in:

/var/log/system.log
/Users/$USERNAME/Library/Logs/DiscRecording.log
/private/var/.logs_exporter/cache/Users/$USERNAME/Library/Logs/DiscRecording.log

HFS/HFS+ date and time values

In HFS+ date and time values are stored in an unsigned 32-bit integer containing the number of seconds since January 1, 1904 at 00:00:00 (midnight) UTC (GMT). This is slightly different from HFS where the date and time value are stored using the local time. The maximum representable date is February 6, 2040 at 06:28:15 UTC (GMT). The date values do not account for leap seconds. They do include a leap day in every year that is evenly divisible by four. This is sufficient given that the range of representable dates does not contain 1900 or 2100, neither of which have leap days. Also see: Technical Note TN1150 - HFS Plus Volume Format

Converting HFS/HFS+ date and time values with Python:

import datetime

print datetime.datetime( 1904, 1, 1 ) + datetime.timedelta( seconds=0xCBDAF25B )

Launch Agents

/System/Library/LaunchAgents/

Launch Daemons

/Library/LaunchDaemons/
/System/Library/LaunchDaemons/

Startup Items

/Library/StartupItems/
/System/Library/StartupItems/

Quarantine event database

See [1]

Snow Leopard and earlier

/Users/$USER/Library/Preferences/com.apple.LaunchServices.QuarantineEvents
SELECT datetime(LSQuarantineTimeStamp + 978307200, "unixepoch") as LSQuarantineTimeStamp, LSQuarantineAgentName, LSQuarantineOriginURLString, LSQuarantineDataURLString from LSQuarantineEvent;

Lion and later

/Users/$USER/Library/Preferences/com.apple.LaunchServices.QuarantineEventsV2

sleepimage

This file is similar to the hibernation file on Windows.

/private/var/vm/sleepimage

Also see: [2]

Package Files (.PKG)

Package Files (.PKG) are XAR archives [3] that contain a cpio archive and metadata [4].

Also see

Formats

External Links

Apple Examiner

iCloud